Hello,
yes, you can serve multiple domains from different ADs with one configuration if a) a trust relationship exists between the ADs (for authentication) and b) you have at least one directory that serves all the user / group information.
We had a customer once with 4 main ADs / domains for different regions of the world. They had a trust relationship between the domain controllers for authentication and synchronized local directory structures into one central directory with one root tree that we used to run our LDAP synchronization against.
Regards
Axel